JVM_IR: call serialization for IR.

Serializer for IR is called when -Xserialize-ir flag is set.

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.kt

@@ -499,6 +499,12 @@ default: `indy-with-constants` for JVM target 9 or greater, `inline` otherwise""
     )
     var typeEnhancementImprovementsInStrictMode: Boolean by FreezableVar(false)
 
+    @Argument(
+        value = "-Xserialize-ir",
+        description = "Save IR to metadata (EXPERIMENTAL)"
+    )
+    var serializeIr: Boolean by FreezableVar(false)
+
     override fun configureAnalysisFlags(collector: MessageCollector, languageVersion: LanguageVersion): MutableMap<AnalysisFlag<*>, Any> {
         val result = super.configureAnalysisFlags(collector, languageVersion)
         result[JvmAnalysisFlags.strictMetadataVersionSemantics] = strictMetadataVersionSemantics